Here you can see my implementation of Interface to C++ class, here the files where you can test the issue. Crash happens if you attempt to rename Category of blueprint implementation of an interface event as shown on screenshots.
http://puu.sh/qKlwk.png → implement function http://puu.sh/qKly0.png → double click on category http://puu.sh/qKlqS.png → accept or cancel any value leads to crash.
[2016.08.22-15.14.38:153][194]LogCrashTracker:
[2016.08.22-15.14.38:153][194]LogWindows:Error: === Critical error: ===
Fatal error!
It’s not a problem, in general.